Question: Simplify the following expression: $k = \dfrac{1}{7t} + \dfrac{9}{8t}$
Answer: In order to add expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $7t$ and $8t$ $\lcm(7t, 8t) = 56t$ $ k = \dfrac{8}{8} \cdot \dfrac{1}{7t} + \dfrac{7}{7} \cdot \dfrac{9}{8t} $ $k = \dfrac{8}{56t} + \dfrac{63}{56t}$ $k = \dfrac{8 +63}{56t}$ $k = \dfrac{71}{56t}$